A photocathode is a metallic or semiconducting cathode that may emit electrons upon the receipt of photons. Alkali antimonide films may be used in photocathodes. Photocathodes may be used in many applications including photodetectors and light sources. A photocathode may be an element in vacuum-tube-based photodetectors, such as discrete-dynode photomultipliers or microchannel-based photomultipliers. A photocathode of a photodetector may dictate the fundamental detector properties including quantum efficiency (QE), wavelength response, dark current behavior, and time response.